Stowage bin assemblies, such as those found in passenger cabins on commercial aircraft include mechanisms that utilize a rotary hinge assembly linking the bin door and the stowage bin. The hinge assembly includes a torsion spring that is torqued to move the stowage bin door from a closed position to an open position. Several airlines include different door assemblies involving doors of various weights and sizes. Utilizing a single or universal rotary hinge assembly can therefore produce variations in terms of the opening time of the door, based on weight and geometry of the attached stowage bin door. That is, the rotary hinge assembly will open faster based on a light weight stowage bin door as opposed to a heavier stowage bin door.
There is a general desire in the field to be able to adjustably compensate a rotary hinge assembly based on the weight and geometry of the stowage bin door in order to prevent the door from opening too abruptly or too slowly.
Therefore and according to one aspect of this application, there is provided an adjustable damper for a rotary hinge assembly utilized for opening and holding open a stowage bin door, said hinge assembly comprising:                a hinge housing including at least one interior chamber;        a rotor rotatably disposed within said at least one interior chamber of said hinge housing, said rotor including at least one movable rotor vane;        a stator stationarily disposed within said at least one interior chamber of said hinge housing, said stator including at least one stator vane, said rotor and said stator combining to foam a fluidic damper;        a fill plug, a portion of said fill plug being disposed between said rotor and stator vanes and including entrance and exit holes for damping fluid defining a fluidic path for said damper;        an adjustable valve for varying the resistance of the fluidic damper; and        a spring means disposed within said at least one interior chamber of said hinge housing for biasing the stowage bin door from a closed position to an open position.        
In one version and in the adjustable damper portion of the rotary hinge assembly, there are two sets of vanes. A set of stator vanes are stationarily disposed while a set of corresponding rotor vanes are caused to rotate in relation to the stator vanes when the stowage bin door is opened or closed. Running the length of the vanes along a center axis of the rotary hinge assembly is the fill plug wherein damping fluid is metered between the sets of vanes. As noted, the fill plug includes a set of entrance holes and exit holes defining a fluidic path for the damper. As the rotor vanes rotate towards the stator vanes, damping fluid is pressurized and thus moved from one side of the rotor vanes to the other side by traveling through the entrance holes to the exit holes of the fill plug. Preferably, the valve is disposed in the center of the fill plug, the valve being adjustable to open, close or otherwise restrict the flow of damping fluid by selectively either opening or restricting at least a portion of the entrance and exit holes of the fill plug.
In one version, the adjustable valve is defined by a movable pin that is disposed within a center bore of the fill plug, the pin being movable so as to selectively open and close at least a portion of the entrance and exit holes of the fill plug.
According to another aspect of this application, there is provided a method for adjustably damping a rotary hinge assembly, said method comprising the steps of:                providing a rotor having rotor vanes;        providing a stator having stator vanes;        moving the rotor relative to the stator in which a retained fluid is moved from one side of said rotor vanes to the other;        providing a fill plug having entrance and exit holes within said fill plug and extending between said rotor vanes and said stator vanes, said entrance and exit holes defining a fluidic path; and        selectively adjusting the size of said entrance and exit holes of said fill plug.        
According to one version, an adjustable valve is provided to perform the selective adjustment step. The adjustable valve can, for example, be provided in the form of a movable or adjustable pin that is rotatably disposed within a recess provided in the fill plug.
The fill plug rotates with the rotor according to one version of the hinge assembly in which a plug member is further included that provides a sealing function and defines a fluidic damping chamber, the plug member being sealingly attached to said rotary hinge assembly and retaining the fill plug. The plug member includes an axial opening that permits a user to access the movable pin and permits adjustment of the damper without requiring disassembly of the herein described rotary hinge assembly.
One advantage that is realized by the present invention is that the torque variation acting on the rotary hinge assembly from the weight and geometry differences of a hinged bin door can effectively be compensated for through the adjustable damping feature of the rotary hinge assembly.
Another advantage provided is that any adjustments can easily be made to the rotary hinge assembly without requiring disassembly or modifications.
Yet another advantage provided is that the operating life of the hinge can be extended in use by adjusting the damping to compensate for wear of components over time in use.
These and other advantages and features will become readily apparent from the following Detailed Description, which should be read in conjunction with the accompanying drawings.